use Tab API to work with worksheets.
If you want to copy from sheet2, then activate and focus on sheet2 and then copy from it.
var T = this.Tab();
T.activate(1); //assuming sheet2 is at 1 index in tabs array collection.
var grid2 = T.grid( T.activeTab());
grid2.focus({rowIndxPage: 1, colIndx: 1});
grid2.Range({r1:1,c1:1, rc:2,cc:2}).copy();